Risk factors for lymphatic filariasis and mass drug administration non-participation in Mandalay Region, Myanmar

Abstract Background: Myanmar commenced a lymphatic filariasis (LF) elimination program in 2000. Whilst the country has made considerable progress since then, a number of districts have demonstrated persistent transmission after many rounds of mass drug administration (MDA). The causes of unsuccessful MDA have been examined elsewhere, however, there remains little information on the factors that contribute in Myanmar. Methods: We conducted an analysis of factors associated with persistent infection, LF-related hydrocoele and MDA participation in an area with ongoing transmission in 2015. A cross-sectional household survey was undertaken in 24 villages across four townships of Mandalay Region. Participants were screened for circulating filarial antigen (CFA) using immunochromatographic tests and if positive, for microfilaria by night-time thick blood slide. Individuals 15 year and older were assessed for filariasis morbidity (lymphoedema and if male, hydrocoele) by ultrasound-assisted clinical examination. A pre-coded questionnaire was used to assess risk factors for LF and for never-taking MDA. Significant variables identified in univariate analyses were included in separate step-wise multivariate logistic regressions for each outcome. Results: After adjustment for covariates and survey design, being CFA positive was significantly associated with age (odds ratio (OR) 1.03, 95% CI 1.01 – 1.06), per year), male gender (OR 3.11, 1.23 – 7.87), elevation (OR 0.97, 0.94 – 1.00, per metre) and the density of people per household room (OR 1.56, 1.26 – 1.93). LF-related hydrocoele was associated with age (OR 1.06, 1.02 – 1.09, per year) and residing in Amarapura Township (OR 8.56, 1.33 – 55.22). Never-taking MDA was associated with age (less than 15 years: OR 2.89, 1.11 – 7.51; greater than 60 years: OR 4.00, 1.53 – 10.48), male gender (OR 1.85, 1.05 – 3.25), residing in Amarapura township (OR 2.99, 1.39 – 6.43), moving to one’s current village from another (OR 2.84, 1.15 – 7.02) and ever having declined medication (OR 13.76, 4.79 – 39.58). Decreased likelihood of never taking MDA was associated with a higher proportion of household members being present during the last MDA round (OR 0.18, 0.04 – 0.96)).Conclusions: These results contribute to the understanding of LF and MDA participation related risk factors, and will assist Myanmar improve its elimination and morbidity management programs.